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  • From: realfood@wonderfulfarm.com
  • To: "Healthy soil and sustainable growing" <livingontheland@lists.ibiblio.org>
  • Subject: Re: [Livingontheland] New info on ug99 wheat disease
  • Date: Tue, 16 Jun 2009 12:48:20 -0700

More reasons why it is so important to remineralize the soils - high brix plants are not prone to these types of disease problems.  We need more diversity in crops not more folks growing only one type because it is resistant to a specific fungus.  JMHO

Blessings,

Aliza


“Don’t ask what the world needs. Ask what makes you come alive, and go do it. Because what the world needs is people who have come alive.” Howard Thurman

-------- Original Message --------
Subject: [Livingontheland] New info on ug99 wheat disease
From: "Liz" <liz@allslash.org>
Date: Tue, June 16, 2009 4:19 am
To: <livingontheland@lists.ibiblio.org>

This article is from two years ago, but there are many other more recent
ones. Here are a couple of links from this year:

http://deltafarmpress.com/wheat/wheat-rust-0417/

http://www.guardian.co.uk/environment/2009/mar/19/rust-fungus-global-wheat-crops

http://www.latimes.com/news/nationworld/nation/la-sci-wheat-rust14-2009jun14,0,365785,full.story

Billions at risk from wheat super-blight
03 April 2007
Exclusive from New Scientist Print Edition.

"This thing has immense potential for social and human destruction."
Startling words - but spoken by the father of the Green Revolution, Nobel
laureate Norman Borlaug, they are not easily dismissed.

An infection is coming, and almost no one has heard about it. This infection
isn't going to give you flu, or TB. In fact, it isn't interested in you at
all. It is after the wheat plants that feed more people than any other
single food source on the planet. And because of cutbacks in international
research, we aren't prepared. The famines that were banished by the advent
of disease-resistant crops in the Green Revolution of the 1960s could
return, Borlaug told New Scientist.

The disease is Ug99, a virulent strain of black stem rust fungus (Puccinia
graminis), discovered in Uganda in 1999. Since the Green Revolution, farmers
everywhere have grown wheat varieties that resist stem rust, but Ug99 has
evolved to take advantage of those varieties, and almost no wheat crops
anywhere are resistant to it.

The strain has spread slowly across east Africa, but in January this year
spores blew across to Yemen, and north into Sudan (see Map). Scientists who
have tracked similar airborne spores in this part of the world say it will
now blow into Egypt, Turkey and the Middle East, and on to India, lands
where a billion people depend on wheat.

There is hope: this week scientists are assessing the first Ug99-resistant
varieties of wheat that might be used for crops. However, it will take
another five to eight years to breed up enough seed to plant all our wheat
fields.

The threat couldn't have come at a worse time. Consumption has outstripped
production in six of the last seven years, and stocks are at their lowest
since 1972. Wheat prices jumped 14 per cent last year.

Black stem rust itself is nothing new. It has been a major blight on wheat
production since the rise of agriculture, and the Romans even prayed to a
stem rust god, Robigus. It can reduce a field of ripening grain to a dead,
tangled mass, and vast outbreaks regularly used to rip through wheat
regions. The last to hit the North American breadbasket, in 1954, wiped out
40 per cent of the crop. In the cold war both the US and the Soviet Union
stockpiled stem rust spores as a biological weapon.

After the 1954 epidemic, Borlaug began work in Mexico on developing wheat
that resisted stem rust. The project grew into the International Maize and
Wheat Improvement Center, known by its Spanish acronym CIMMYT. The
rust-resistant, high-yielding wheat it developed banished chronic hunger in
much of the world, ended stem rust outbreaks, and won Borlaug the Nobel
peace prize in 1970.

Yet once again Borlaug - now 93 and fighting cancer - is leading the charge
against his old enemy. When Ug99 turned up in Kenya in 2002, he sounded the
alarm. "Too many years had gone by and no one was taking Ug99 seriously," he
says. He blames complacency, and the dismantling of training and wheat
testing programmes, after 40 years without outbreaks.

Now a Global Rust Initiative (GRI) is under way at CIMMYT. It's head, Rick
Ward, blames the delay on cuts, starting in the 1980s, in CIMMYT's funding
for routine monitoring and maintenance of crops and pests.

"CIMMYT was slow to detect the extent of susceptibility to Ug99 [because] it
didn't have the scientific eyes and ears on the ground any more," says Chris
Dowswell of CIMMYT. "Once it did, it had to start a laborious fund-raising
campaign to respond."

Ward is now being promised adequate support as fears grow in rich
wheat-growing countries, but meanwhile Ug99 has got worse. It was first
noticed because it started appearing on wheat previously protected by a gene
complex called Sr31, the backbone of stem rust resistance in most wheat
farmed worldwide. Then last year it acquired the ability to defeat another
widely used complex, Sr24. "Of the 50 genes we know for resistance to stem
rust, only 10 work even partially against Ug99," says Ward. Those are
present in less than 1 per cent of the crop.

The first line of defence is fungicide, but the poor farmers who stand to
lose most from the blight generally cannot afford it, or don't have the
equipment or know-how to apply it. CIMMYT is considering "fire brigade"
spray teams armed with cheap, generic fungicides in poor areas. However,
they will be competing with the rich for fungicide, and depending on where
Ug99 strikes, stocks could be limited.

Even rich countries face problems. The US has been fighting soybean rust
with fungicide ever since spores blew in on hurricane Ivan in 2004. If Ug99
arrives as well, the US could be in trouble because it doesn't make enough
fungicide for both crops. Kitty Cardwell of the US Department of Agriculture
says there might be enough if the US fights Ug99 the same way as it is
tackling soya rust: spotting outbreaks with a fast DNA-based field test and
posting the results on an interactive website (www.sbrusa.net), so farmers
spray only when danger looms. Ultimately, says Ward, the only real answer
"is to get new, resistant varieties out there".

CIMMYT has been working on this by taking countries' top-yielding varieties
and crossing them with wheat from its seed collections that does resist
Ug99. For two years now the crosses have been tested for resistance at field
stations in Njoro, Kenya, and in Ethiopia, where it is safe to release Ug99
as it is already there. Resistant strains are sent back to CIMMYT in Mexico
and assessed for yield and other qualities, then sent out again for further
tests. Resistant lines are now being grown on 27 plots in Nepal, India,
Afghanistan and Pakistan.

So far so good, but the real challenge is multiplying up enough resistant
seed so that if Ug99 hits, there will be enough to plant the next crop. This
takes time - and it will only happen if the new resistant varieties match or
exceed existing yields. Nor is it an exact science. No one knows why wheat
that looks good in Mexico might grow as well in Egypt, say, but fail in
China unless it is crossed with a local variety.

There is nothing for it but to do the tests, says Ravi Singh, the GRI's
chief wheat pathologist. The resistant lines must be just as good as the
ones people are growing now, he says, or farmers won't use them, and
government-owned seed companies that dominate the wheat industry in
developing countries won't sell them, no matter what new disease the
scientists say is coming.

Singh calculates that if he can get countries to devote 3 to 5 per cent of
their wheat-growing area to resistant varieties, the seed harvest will be
enough to plant the whole country with resistant wheat if Ug99 hits.

So it's a race, and who wins depends on what Ug99 does now. Stem rust can
arrive in a new area and lurk for years before it gets the right conditions
for an outbreak. "It won't suddenly explode everywhere. It will be like a
moving storm," says Dowswell.

However, Ug99 has another ace up its sleeve. The spores blowing in the wind
now are from the asexual stage that grows on wheat. If any blow onto the
leaves of its other host, the barberry bush (Berberis vulgaris), they will
change into the sexual form and swap genes with whatever other stem rusts
they find. Barberry is native to west Asia. "As if it wasn't challenging
enough breeding varieties that resist this thing," laments Ward. "All I know
is that what blows into Iran will not be the same as what blows out."

What's more, Ug99 will find agriculture has changed to its liking in the
decades stem rust has been away. "Forty years ago most wheat wasn't
irrigated and heavily fertilised," says Borlaug. Now, thanks to the Green
Revolution he helped bring about, it is. That means modern wheat fields are
a damper, denser thicket of stems, where dew can linger till noon - just
right for fungus.

Another worry is that travel has exploded in the past 40 years. There have
now been several documented cases of travellers carrying rust spores on
their clothing. Some fear Ug99 will hitchhike as much as it flies - and its
spread need not be innocent. New Scientist has learned that the US
Department of Homeland Security met in March to discuss the possibility that
someone could transport Ug99 deliberately.

Even at 93, Borlaug is looking to the long term. Eventually, scientists will
have to create wheat with a wide spectrum of resistances. The genes may be
hiding in other grains and grasses. "Why has rice had no rusts for millions
of years?" he asks.

For now, Borlaug says, we have to rely on fungicides, wheat breeding and
luck. "We're moving as fast as we can now, but we started three years too
late," he says. "We'd better have some good luck. Governments think this is
still small and local, but these things build up."

>From issue 2598 of New Scientist magazine, 03 April 2007, page 6-7


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